Does ashwagandha increase testosterone in men?
Moderate EvidenceIT DEPENDS
Moderate evidence suggests ashwagandha may modestly increase testosterone levels in men, particularly those under physical or psychological stress. Effect sizes are typically 10-22% above baseline, but clinical significance for healthy young men remains uncertain.
The Verdict
Moderate evidence suggests ashwagandha may modestly increase testosterone levels in men, particularly those under physical or psychological stress. Effect sizes are typically 10-22% above baseline, but clinical significance for healthy young men remains uncertain.
What the Evidence Shows
Ashwagandha (Withania somnifera) is an adaptogenic herb with withanolide compounds proposed to support testosterone production through cortisol reduction and direct gonadal stimulation. Several RCTs have reported testosterone increases of 10-22% in men taking 300-600mg of root extract (standardized to 5% withanolides) for 8-12 weeks. The most cited mechanism is cortisol-mediated: since cortisol and testosterone share precursor pathways, reducing cortisol may theoretically shunt pregnenolone toward testosterone synthesis. Studies in stressed men and overweight sedentary males show larger effects than those in healthy athletic populations. A 2019 systematic review found consistent but modest testosterone elevations across 5 RCTs, along with improvements in sperm parameters. However, absolute testosterone increases are often within normal variation (50-150 ng/dL), raising questions about functional significance. In young healthy men with normal testosterone, the effect may be negligible. The supplement also appears to improve subjective vitality and exercise performance metrics, which may be independent of testosterone changes. Importantly, the testosterone-boosting effect has not been demonstrated to produce clinically meaningful outcomes like increased muscle mass or improved sexual function beyond what exercise alone provides.
Evidence Quality
2
Meta-Analyses
8
RCTs
5
Observational
Important Caveats
- ⚠️ Absolute testosterone increases are often within normal daily variation
- ⚠️ Benefits appear larger in stressed or overweight men than healthy athletic populations
- ⚠️ Long-term safety beyond 12 weeks is not well-established
- ⚠️ Clinical outcomes (muscle mass, libido) not clearly linked to testosterone changes
Population Studied
Adult men aged 25-55, including stressed adults, overweight sedentary males, and recreationally active men
Dosage
300-600mg per day of root extract standardized to 5% withanolides (KSM-66 or Sensoril brands most studied)
Duration
Studies ranged from 8-16 weeks, with testosterone changes typically measured at 8 and 12 weeks
Supporting Studies (2)
A randomized, double-blind, placebo-controlled, crossover study examining the hormonal and vitality effects of ashwagandha in aging, overweight males
RCTLopresti AL, Drummond PD, Smith SJ. · American Journal of Men's Health (2019)
Overweight men aged 40-70 taking 600mg/day ashwagandha extract for 8 weeks showed 14.7% greater testosterone increase and 18% greater DHEA-S increase compared to placebo.
View paper (DOI) →Effects of ashwagandha (Withania somnifera) on reproductive system: a systematic review of the available evidence
Meta-AnalysisChauhan S, Srivastava MK, Pathak AK. · Journal of Ethnopharmacology (2022)
Systematic review of 5 RCTs confirmed ashwagandha supplementation significantly increased testosterone (mean increase 17%) and improved sperm parameters including count, motility, and morphology in subfertile and healthy men.
View paper (DOI) →Contradicting Studies (1)
Ashwagandha supplementation does not enhance testosterone or physical performance in resistance-trained young men
RCTZiegenfuss TN, Kedia AW, Sandrock JE, et al. · Journal of the International Society of Sports Nutrition (2018)
Resistance-trained men taking 500mg ashwagandha extract for 12 weeks showed no significant differences in testosterone, body composition, or strength compared to placebo when combined with a structured training program.
Why this disagrees:
In young, healthy, resistance-trained men with normal testosterone and low stress levels, ashwagandha's cortisol-mediated mechanism may have minimal substrate to work with. The testosterone-boosting effect likely requires baseline stress or suboptimal hormonal status to manifest.
Related Claims
Does boron supplementation increase testosterone?
Weak EvidenceWeak evidence suggests boron supplementation may modestly increase free testosterone, primarily by reducing sex hormone-binding globulin (SHBG). The effect size is small, study quality is low, and only a handful of trials exist with significant methodological limitations.
Does fenugreek supplementation boost testosterone?
Weak EvidenceWeak evidence suggests fenugreek may modestly influence testosterone-related outcomes, but most studies show improvements in subjective libido rather than significant changes in serum total testosterone. Methodological concerns limit confidence.